Comparison of the Carpentier and Duran Prosthetic Rings Used in Mitral Reconstruction

Transcription

1 Comparson of the Carpenter and Duran Prosthetc Rngs Used n Mtral Reconstructon Yukkatsu Okada, MD, Toyo Shomura, MD, Yasuko Yamaura, MD, and Junch Yoshkawa, MD Departments of Thoracc and Cardovascular Surgery, and Cardology, Kobe General Hosptal, Kobe, Japan Ths clncal study was undertaken to evaluate the Duran flexble rng and the Carpenter rgd rng n terms of mtral annulus moton, transmtral flow and left ventrcular functon. Twenty-sx patents (11 recevng rgd rngs and 15, flexble rngs) wth normal snus rhythm and wth no or only trval mtral valve regurgtaton after surgcal repar were selected. Angograms demonstrated no sgnfcant dfferences n left ventrcular systolc functon between the two groups of patents. The area of the mtral annulus wth the flexble rng sgnfcantly changed durng the cardac cycle. There were sgnfcant dfferences n the left ventrcular fractonal shortenng (rgd rng, 35.8%; flexble rng, 43.4%) and n the peak velocty (rgd rng, 222 cm/s; flexble rng, 186 cm/s) at peak exercse. These data suggest that the flexble rng nterferes less wth the normal movements of the mtral annulus durng the cardac cycle, and that, under exercse condtons, t performs better than the rgd rng. We therefore conclude that mtral valve reconstructon usng the Duran flexble rng s advantageous n patents wth mtral regurgtaton due to degeneratve dsease and snus rhythm. (Ann Thorac Surg 1995;59:658-63) p rosthetc annuloplasty rngs are currently used n mtral reconstructon. Although a varety of models are currently avalable, they all conform to two basc types: the rgd rng developed by Carpenter and assocates [1], whch restores the mtral annulus to ts normal systolc sze and shape, and the totally flexble rng descrbed by Duran and Umbago [2, 3], whch also reduces the annulus sze but allows for t to contnuously change durng the cardac cycle. In general the arguments for and aganst each type reman rather theoretcal and there s an obvous lack of objectve data supportng ether poston. In an expermental study, van Rjk-Zwkker and co-workers [4] showed a larger effectve mtral orfce wth the Duran rng than wth the Carpenter, but small dfferences n left ventrcular pump functon. Davd and assocates [5], n a clncal study consstng of 25 patents wth degeneratve chronc mtral valve regurgtaton undergong repar wth both types of rngs, showed better systolc left ventrcular functon at 2 to 3 months after repar n those patents wth a flexble rng. Doppler echocardogram-based clncal comparsons [6, 7] have shown that both rngs decrease the mtral valve area but wthout producng a clncally sgnfcant ncrease n the transvalvular gradents. In an attempt to further elucdate ths ssue, a clncal comparatve study was undertaken to evaluate the possble dfferences between the two rngs n terms of the mtral annulus sze and moton, transmtral flow, and left ventrcular functon. Accepted for publcaton Nov 14, Address reprnt requests to Dr Okada, Department of Thoracc and Cardovascular Surgery, Kobe General Hosptal, 4-6 Mnatojmanakamach Chuou-ku Kobe, Japan, 650. Patents and Methods Between June 1987 and December 1993, 107 patents underwent mtral valve repar at our nsttuton. A Carpenter or Duran rng was mplanted wth nterrupted sutures n 71% of them. For the purpose of ths study, 26 patents were selected who met the followng crtera: (1) they were operated on for chronc mtral regurgtaton secondary to degeneratve dsease; (2) they had snus rhythm postoperatvely; (3) they had no or trval resdual regurgtaton postoperatvely; and (4) they underwent no other concomtant surgcal procedure. Eleven patents receved a Carpenter rng and 15, a Duran rng. The sze of the rgd rng was selected accordng to the sze of the anteror leaflet; the sze of the flexble rngs was based on the ntertrgonal dstance. The clncal and echocardographc data for both groups of patents are gven n Table 1. There were no sgnfcant dfferences between the groups, except n the sze of the rng used. Postoperatve contrast-enhanced left ventrculograms were obtaned n all patents wthn 1 month of mtral valve repar. The left ventrcular volumes were calculated usng the standard area-to-length method (left ventrcular end-dastolc and end-systolc volume ndex, both n mlllters per square meter). The left ventrcular ejecton fracton and stroke volume ndex (n mlllters per square meter) were also calculated. Left ventrcular segmental wall moton was analyzed by the center-lne method [8] usng the Cardo 500 system (Kontron, Germany). Wall moton was measured along 100 chords constructed perpendcular to a center lne drawn mdway between the end-dastolc and end-systolc contours. The measured moton of the 100 chords was normalzed for heart sze by dvdng t by the length of the end-dastolc 1995 by The Socety of Thoracc Surgeons /95/$ (94)01008-Z

2 Ann Thorac Surg OKADA ET AL ;59: CARPENTIER AND DURAN PROSTHETIC RINGS Table 1. Clncal Characterstcs of the 26 Patents Studed a Rgd Rng Flexble Rng Varables (n = 11) (n = 15) p Value Preoperatve Age (y) Sex Body surface area (m z) Rng sze NYHA class Snus rhythm Left ventrcular dastolc dameter (cm) Postoperatve NYHA class Snus rhythm Mtral regu.rgtaton area (cm z) Left ventrcular systolc dameter (cm) 53.5 ± ± 8.7 Male (7) Male (12) Female (4) Female (3) 1.58 ± ± (1) 27 (6) 30 (4) 29 (8) 32 (6) 33 (1) II (9) II (12) III (2) III (3) (11) (15) 6.3 ± ± 0.2 I (11) I (15) (11) (15) _ ± ± 0.5 a Data are shown as the mean + the standard devaton. Numbers parentheses are numbers of patents. = not sgnfcant; NYHA = New York Heart Assocaton. permeter. The left ventrcular wall (rght anteror oblque projecton) was dvded nto ten segments and the segmental wall moton was expressed as the mean value of ten chords of normalzed moton. Left ventrcular segmental wall moton was then compared between the two groups of patents. Contnuous-wave Doppler and two-dmensonal echocardograms were obtaned 6 months after repar to assess mtral dastolc flow and left ventrcular functon at rest and also durng exercse on a bcycl e ergometer wth the patent n the supne poston. Toshba SSH 160A (Tokyo, Japan) and Aloka SSD870 (Tokyo, Japan) echo systems were used n these studes. Transmtral flow characterstcs were defned n terms of the peak velocty and mean velocty, both rendered n centmeters per second. Fractonal shortenng was evaluated at rest and durng exercse. Table 2. Left Ventrcular Functon Usng Area Length Method a Rng LVEDVI LVESVI Type (ml/m 2) (ml/m 2) SI (ml/m 2) LVEF (%) Flexble ± ± 6 Rgd 80 ± ± ± ± 10 Data are shown as the mean -+ the standard devaton. There are no sgnfcant dfferences between flexble and rgd rngs for any varable. LVEDVI = left ventrcular end-dlastolc volume ndex; LVEF = left ventrcular ejecton fracton; LVESVI = left ventrcular end-systolc volume ndex; = not sgnfcant; SI = stroke ndex. n normalzed % ~oton z r-- r--t r--1 Ns Ns T T TT T -L T TT s ~ P < segment [] rgd rng flexble rng Fg 1. Left ventrculograms n rght anteror oblque projecton were used for ths analyss. Left ventrcular wall was dvded nto ten segments, and each segmental wall moton s presented as normalzed moton. There s a sgnfcant dfference n segment 10. ( = not sgnfcant.) To evaluate the sze and moton of the mtral annulus after rng mplantaton, the two-dmensonal echocardography [9] was performed n all patents at 9 months n those wth the Duran rng and at 30 months n those wth the Carpenter rng. The mtral annulus wth the prosthetc rng was recorded from a vew close to the standard apcal four-chamber vew. The transducer was rotated and recordngs were made at 30-degree rotatonal ntervals around the crcumference of the mtral valve annulus. To reconstruct the annulus, dameters from each rotatonal nterval were arranged around a refer- c- e ' o....~....~....o-..~... Duran sze 27 ~ ± Duran sze 29 I --o-. Carpenter sze 30 --o-. Carpenter sze Fg 2. Area of the mtral annulus wth the Carpenter rgd rng does not change durng the cardac cycle, but the area of the mtral annulus wth the Duran flexble rng changes smlar to that occurrng n normal subjects.

3 660 OKADA ET AL Ann Thorac Surg CARPENTIER AND DURAN PROSTHETIC RINGS 1995;59: ence pont eght tmes durng the cardac cycle. The area of the mtral annulus wth the prosthetc rng was then measured wth a planmeter. All data are presented as the mean + standard devaton. Comparsons between the patents wth a rgd rng and those wth a flexble rng were done usng the Mann-Whtney U test for grouped data. The dfference was consdered sgnfcant at a p level of less than X.' -.X- * -X- 4(" -X- * l--] I l-'-i l--- I 'l l l l l l I I I I I 100 ~ ~. I I I,< 9O Results As shown n Table 2, the left ventrcular end-dastolc volume ndex was, on average, 7% less n the patents wth the rgd rng, but ths dfference was not statstcally sgnfcant. Although the stroke ndex and left ventrcular ejecton fracton n those wth the flexble rng were greater than those n the patents wth the rgd rng, these dfferences also were not statstcally sgnfcant. There was no sgnfcant dfference between the two groups n the length of the center lne (rgd rng, cm; flexble rng, cm). Normalzed moton wth the flexble rng was greater from segments 5 to 10, but ths dfference was not statstcally sgnfcant except for segment 10 (Fg 1). Two-dmensonal echocardography demonstrated that the area of the mtral annulus wth the rgd rng dd not change sgnfcantly durng the cardac cycle. By I t anteror posteror 0-- w --0 = Boundary of mltrsl annulus wth the flexble rng reconstructed concdent wth the P wave H = Boundary of mtral annulus wth the flexble rng at mdsystole Fg 3. Reconstructed mtral annulus wth a Duran flexble rng. The sold lne represents the mnmum area and the dashed lne demonstrates the maxmum area. I " 80 I l l~ J I r- I I I ~'l"/j- l I I ~ I I I I 1" I I 70 I Ill ~- I I ~- I IJl I I I Ill I l I I ll l I ~J~ I 60 I I/ 1 I /" I'~ I 1 I 1!1 I I I I I I I I T8 T1 T2 T3 T4 T5 T6 ]'7 T8 Fg 4. Area of the mtral annulus wth the flexble rng changes sgnfcantly durng the cardac cycle. Percentage reducton n the sze of the mtral annulus area wth the flexble rng s, on average, 26% + 4% of the maxmum area at P wave. ( = not sgnfcant; T = tme; *p < 0.05.) contrast, the area of the mtral annulus wth the flexble rng dd change durng the cardac cycle (Fg 2). The area reconstructed concdental wth the P wave was maxmal, followed by presystolc and systolc narrowng to the mnmal sze at mdsystole. The maxmum area acheved wth the sze 29 flexble rng corresponded to the area acheved wth the sze 32 rgd rng. The mnmal area of the sze 29 flexble rng at mdsystole was smaller than that of the sze 30 rgd rng. In other words, the sze 29 flexble rng functoned smlarly to a sze 32 rgd rng at dastole and a sze 30 rgd rng at systole. The posteror mtral annulus wth the flexble rng contracted and moved anterorly (Fg 3). The percentage reducton n the area of the flexble rng durng the cardac cycle was 26% - 4% (Fg 4). Ths change s smlar to that noted for the annulus of normal subjects [9]. Supne exercse sgnfcantly ncreased heart rate and systolc blood pressure n both groups (Fg 5). Exercse workloads were watts n the patents wth the rgd rng and watts n the patents wth the flexble rng (p = not sgnfcant). There were no sgnfcant dfferences n heart rate and systolc pressure between the two groups ether at rest or durng peak exercse. Fgure 6 demonstrates the changes n the fractonal shortenng, peak velocty, and mean velocty across the mtral valve at rest and durng peak exercse. At rest, there were no sgnfcant dfferences between the two groups n the left ventrcular fractonal shortenng (rgd rng, 36.2% %; flexble rng, 37.1% + 9.4%), peak velocty (rgd rng, cm/s; flexble rng, cm/s), and mean velocty (rgd rng, 91 _+ 23 cm/s, flexble rng, 70 _+ 20 cm/s). Durng exercse, fractonal shortenng n the patents wth the flexble rng ncreased sgnfcantly, whereas t dd not change sgnfcantly n

4 Ann Thorac Surg OKADA ET AL ;59: CARPENTIER AND DURAN PROSTHETIC RINGS BPM 16o 120 heart rate mmhg 200 systolc blood pressure N S Fg 5. Supne exercse sgnfcantly ncreased the heart rate and systolc blood pressure n both groups. There are no sgnfcant d;~:erences n ether varable at rest or durng peak exercse. (BPM = beats/mn; = not sgnfcant.) 100 rest exercse rest exercse [---7 rgd rng BB flexble rng the patents wth the rgd rng. Both the peak velocty and mean velocty of transmtral flow ncreased sgnfcantly wth exercse. Durng exercse, there was a sgnfcant dfference n the peak velocty between the two groups, as shown n Fgure 6 (p < 0.05). Comment Our present data demonstrate that the Duran rng nterferes less wth the normal movements of the mtral annulus durng the cardac cycle. Based on the annular area, the sze 29 flexble rng functons lke a sze 32 rgd rng at dastole and a sze 30 rgd rng at systole. In our clncal cases, the mean systolc reducton rate of the mtral annulus area wth the Duran rng was approxmately 26%, but the actual area of the mtral annulus wth the flexble rng was understandably smaller than that of normal subjects. Recently van Rjk-Zwkker and col- leagues [4] demonstrated usng cnefluoroscopy that the end-systolc area of the porcne mtral annulus wth a Duran rng was, on average, 86.3% of the dastolc area. Ths rato dropped to 66.7% after stmulaton wth notropc agents. Usng two-dmensonal echocardography, Ormston and colleagues [9] found that the mean reducton n the mtral annulus area from dastole to systole n normal subjects was 26%; they also dscovered that the moton pattern was smlar to that noted n expermental studes on dogs. Because our echocardographc studes were done wthn 30 months after operaton, further clncal assessment s needed to confrm contnued flexblty of the Duran rng at late follow-up, when ntmal coverage may be more extensve. The peak and mean velocty of dastolc flow across the mtral valve wth the two types of rng are not dfferent from those reported by Unger-Graeber and assocates [6]. We demonstrated that there was a sgnfcant dffer- Fractonal Shortenng % cm/s 70}, p<0.05, 3001 BO, I p''' < 0.05, 5C 40 2(] Peak velocty p < 0.05 p < 0.05 ~ p < 0.05,, t cm/s c mean velocty Fg 6. There s a sgnfcant d~erence n fractonal shortenng durng peak exercse between the two groups (rgd rng, 35.8%; flexble rng, 43.4%). The peak velocty n the patents wth the flexble rng s sgnfcantly slower than that n the patents wth a rgd rng (rgd rng, 222 cm/s; flexble rng, 186 cm/s). ( = not sgnfcant.) 30 2O 1C 10c 10 rest exercse rest exercse rest exercse I--I rgd rng BIB flexble rng

5 662 OKADA ET AL Ann Thorac Surg CARPENTIER AND DURAN PROSTHETIC RINGS 1995;59: ence n peak velocty across the mtral valve between the two groups durng exercse. Rass and colleagues [10] notced that the exercse-nduced ncrease n mtral volume flow was manly due to an ncrease n the maxmum dastolc valve orfce. Our results suggest that a mtral valve repared wth a flexble rng has a larger effectve orfce durng exercse than does a mtral valve wth a rgd rng. The effect of rgd rng fxaton of the mtral annulus on left ventrcular functon has been dscussed for a long tme. Fndngs from an expermental study conducted by Tsakrs and assocates [11] suggested that rgd fxaton of the mtral annulus does not have a harmful effect on the left ventrcle. Spence and assocates [12] compared the respectve effects of rgd and flexble mtral rngs n solated porcne hearts, and found that fxaton of the mtral annulus wth a rgd prosthess was detrmental to systolc functon of the left ventrcle, van Rjk-Zwkker and assocates [4] demonstrated that the effect of rgd support of the annulus could be descrbed as a reducton n pump functon caused by mpared fllng of the left ventrcle, whch lmts stroke volume, partcularly when cardac output s hgh. Castro and assocates [13] recently reported that annuloplasty wth a flexble or rgd rng dd not alter left ventrcular systolc performance n conscous, closed-chest dogs. There are two clncal reports concernng the effect of the type of rng on left ventrcular functon. In 1976, Duran and Ubago [3] demonstrated that there was no statstcally sgnfcant dfference n left ventrcular functon between the two types of rng, although there was a sgnfcant dfference n the systolc shortenng of the basal segments of the left ventrcle measured by angography. Davd and assocates [5] reported that the patents wth a flexble annuloplasty rng had better left ventrcular systolc functon than dd patents wth a rgd annuloplasty rng 2 to 3 months after mtral valve reconstructon for chronc mtral regurgtaton secondary to degeneratve dsease. Although there s no statstcally sgnfcant dfference n the left ventrcular pump functon, the present data show a larger end-dastolc volume, smaller end-systolc volume, and better left ventrcular ejecton fracton n the patents wth the flexble rng. The dastolc fllng across the mtral valve and left ventrcular fractonal shortenng durng exercse were sgnfcantly superor n the patents wth the flexble rng. Left ventrcular pump functon wth the rgd rng s affected not only by mparment of the stretchng and shortenng actons of the basal part of the left ventrcle, but by the dastolc fllng of the left ventrcle. Our present data suggest that mtral repar wth a flexble rng produces results superor to those assocated wth use of a rgd rng n patents wth degeneratve mtral regurgtaton who are n snus rhythm. References 1. Carpenter A, Deloche A, Dauptan J, et al. A new reconstructve operaton for correcton of mtral and trcuspd nsuffcency. J Thorac Cardovasc Surg 1971;61: Duran CMG, Ubago JL. Clncal and hemodynamc performance of a totally flexble prosthetc rng for atroventrcular valve reconstructon. Ann Thorac Surg 1976;22: Duran CMG, Ubago JL. Conservatve mtral valve surgery: problems and developments n the technque of prosthetc rng annuloplasty. In: Kalmanson D, ed. The mtral valve: a plurdscplnary approach. Acton, MA: Publshng Scence Group, 1976: Van Rjk-Zwkker GL, Mast F, Schpperheyn JJ, Huysmans HA, Bruschke AVG. Comparson of rgd and flexble rngs for annuloplasty of the porcne mtral valve. Crculaton 1990;82(suppl IV): Davd TE, Komeda M, Pollck C, Burns RJ. Mtral valve annuloplasty: the effect of the type on left ventrcular functon. Ann Thorac Surg 1989;47: Unger-Graeber B, Lee RT, Sutton MSJ, Plappert M, Collns JJ, Cohn LH. Doppler echocardographc comparson of the Carpenter and Duran annuloplasty rngs versus no rng after mtral valve repar for mtral regurgtaton. Am J Cardol 1991;67: Kenny J, Cohn L, Shemn R, Collns JJ, Plappert M, Sutton MSJ. Doppler echocardographc evaluaton of rng mtral valvuloplasty for pure mtral regurgtaton. Am J Cardol 1987;59: Sheehan FH, Bolson E, Dodge HT, Mathey DG, Schofer J, Woo HW. Advantages and applcatons of the centerlne method for characterzng regonal ventrcular functon. Crculaton 1986;74: Ormston JA, Shah PM, Te C, Wong M. Sze and moton of the mtral valve annulus n man: 1. A two-dmensonal echocardographc method and fndngs n normal subjects. Crculaton 1981;64: Rass A Jr, Crawford MH, Rchards KL, Mller JF. Dfferng mechansms of exercse flow augmentaton at the mtral and aortc valves. Crculaton 1988;77: Tsakrs AG, Rastell GC, Banchero N, Wood EH, Krkln JW. Fxaton of the annulus of the mtral valve wth a rgd rng: hemodynamc studes. Am J Cardol 1967;20: Spence PA, Penston CM, Davd TE, et al. Toward a better understandng of the etology of left ventrcular dysfuncton after mtral valve replacement: an expermental study wth possble clncal mplcatons. J Thorac Cardovasc Surg 1986;41: Castro LJ, Moon MR, Rayhll SC, et al. Annuloplasty wth flexble or rgd rng does not alter left ventrcular systolc performance, energetcs, or ventrcular-arteral couplng n conscous, closed-chest dogs. J Thorac Cardovasc Surg 1993;105: INVITED COMMENTARY Okada and assocates have shown that the moton of the mtral annulus durng the cardac cycle after mtral valve repar for chronc mtral regurgtaton due to degeneratve dsease of the mtral valve s affected by the type of annuloplasty rng used. As I would expect, they found that the shape and area of the mtral annulus dd not change durng the cardac cycle n patents who had annuloplasty wth a Carpenter rng, but they dd so n

6 Ann Thorac Surg OKADA ET AL ;59: CARPENTIER AND DURAN PROSTHETIC RINGS patents who had annuloplasty wth a Duran rng. A more mportant fndng was that the dastolc blood flow across the mtral valve durng exercse was better n patents wth the Duran rng. Ths s new and mportant nformaton. Because the two groups of patents were studed at dfferent postoperatve tme ntervals (9 and 30 months) and the study was not randomzed, the data on left ventrcular functon has to be nterpreted wth cauton. Although we have found that left ventrcular systolc functon soon after operaton s better n patents who had annuloplasty wth a flexble rng than t s n those who had annuloplasty wth a rgd rng, there was no dfference between these two groups 2 years later. Ths observaton suggests that the left ventrcle has compensatory mechansms to overcome the rgd fxaton of the mtral annulus, or that the flexble rng becomes stffer after a few years. Most patents had farly normal left ventrcular functon regardless of the type of annuloplasty rng used. Trone E. Davd, MD Dvson of Cardovascular Surgery The Toronto Hosptal 200 Elzabeth St Toronto, Ontaro M5G 2C4 Canada Notce From the Southern Thoracc Surgcal Assocaton The Forty-second Annual Meetng of the Southern Thoracc Surgcal Assocaton wll be held at the Hyatt Regency Hll Country Resort, San Antono, Texas, November 9-11, The Postgraduate Course wll be held the mornng of Thursday, November 9, 1995, and wll provde n-depth coverage of thoracc surgcal topcs selected prmarly as a means to enhance and broaden the knowledge of practcng thoracc and cardac surgeons. Members wshng to partcpate n the Scentfc Program should submt an orgnal abstract and one copy by May 8, 1995, to Ronald C. Hll MD, Program Charman, Southern Thoracc Surgcal Assocaton, 401 North Mchgan Avenue, Chcago, IL Abstracts must be submtted on the Southern Thoracc Surgcal Assocaton abstract form. These forms may be obtaned from the Assocaton's offce or n ths ssue of The Annals of Thoracc Surgery. Manuscrpts of accepted papers must be submtted to The Annals of Thoracc Surgery pror to the 1995 meetng or to the Secretary-Treasurer at the openng of the Scentfc Sesson. Applcatons for membershp should be completed by August 1, 1995, and forwarded to Carolyn E. Reed, MD, Membershp Commttee Charman, Southern Thoracc Surgcal Assocaton, 401 North Mchgan Avenue, Chcago, IL D. Glenn Pennngton, MD Secretary-Treasurer Southern Thoracc Surgcal Assocaton 401 North Mchgan Avenue Chcago, IL